Only a limited number of molecules with demonstrated therapeutic value can be transported through the skin, even with the use of approved chemical enhancers. The main barrier to transport of molecules through the skin is the stratum corneum (the outermost layer of the skin).
Devices including arrays of relatively small structures, sometimes referred to as microneedles or micro-pins, have been disclosed for use in connection with the delivery of therapeutic agents and other substances through the skin and other surfaces. The devices are typically pressed against the skin in order to pierce the stratum corneum such that the therapeutic agents and other substances can pass through that layer and into the tissues below.
Molding processes to prepare microneedles and microneedle arrays have been previously disclosed, but microneedles are very fine structures that can be difficult to prepare in a polymeric molding process and the known microneedle molding processes all have certain disadvantages.